1. Field of the Invention
The present invention relates to digital decorating or tattooing of living skin using Wirejet(trademark) or similar printing technology. The present invention also relates to digitally decorating adnexal structures of living skin such as hair or nails using Wirejet(trademark) or similar printing technology.
2. Description of Related Art
Decorating the human skin by applying colored inks or dyes to produce temporary decorations or permanent tattoos has a long history. Tattooing by puncturing the skin with a sharp tool or needle to introduce a dye under the uppermost layer of skin was practiced by the Egyptians. The inks used in tattoos are composed of organic and inorganic pigments of varying colors with particles typically larger than 10-50 microns in diameter. The large particle size prevents the particles from being engulfed by the macrophages that reside in the dermis.
To produce a permanent tattoo, these dyes or inks must be injected into the dermis with needles, which limits the degree of detail and leads to irregular penetration depths. This method of tattooing can be painful and possibly dangerous if the needles have not been properly sterilized. In addition, permanent tattoos are undesirable because the wearer often reconsiders after a period of time and then must undergo a removal procedure, which is often expensive, painful, and not 100% effective. Even current laser tattoo removal technology cannot uniformly destroy the pigment and remove the coloration from the skin because of the varying penetration depths of the dyes.
Washable or xe2x80x9crub-onxe2x80x9d tattoos are commercially available which can be easily applied to the epidermis. These decorations are temporary and wear off or wash off with time, typically lasting only a week. Just as in newspapers and newsprint, with xe2x80x9cpress-on or rub-onxe2x80x9d tattoos increasing the number of colors increases the cost, therefore, color multiplicity and availability are extremely limited. Additionally, although these tattoos afford the advantage of being temporary and easily removable, the available designs or images are also limited and not personalized.
Thus, it would be advantageous to provide a digital method for decorating the skin with custom-made, highly detailed, designs. Such designs could provide a more detailed, artful, colorful and xe2x80x9cfresherxe2x80x9d look than xe2x80x9cpress-onxe2x80x9d tattoos that are limited in colors and may look like a xe2x80x9csheetxe2x80x9d. Furthermore, it would be beneficial for the device to apply such skin decorations easily, economically, and quickly, without pain or the risk of injury.
Some inkjets use thermal technology, whereby heat is used to fire ink onto a substrate. There are three main stages with this method. The squirt is initiated by heating the ink to create a bubble until the pressure forces it to burst and hit the paper. The bubble then collapses as the element cools, and the resulting vacuum draws ink from the reservoir to replace the ink that was ejected.
Tiny heating elements are used to eject ink droplets from the print-bead""s nozzles, thermal inkjets have print heads containing between 300 and 600 nozzles in total, each about the diameter of a human hair (approx. 70 microns). These deliver drop volumes of around 8-10 picolitres (a picolitre is a million millionth of a liter), and dot sizes of between 50 and 60 microns in diameter. By comparison, the smallest dot size visible to the naked eye is around 30 microns. Dye-based cyan, magenta and yellow inks are normally delivered via a combined CMY print-head. Several small color ink dropsxe2x80x94typically between four and eightxe2x80x94can be combined to deliver a variable dot size, a bigger palette of non-halftones colors and smoother halftones. Black ink, which is generally based on bigger pigment molecules, is delivered from a separate print-head in larger drop volumes of around 35 pt. Nozzle density, corresponding to the printer native resolution varies between 300 and 600 dpi, with enhanced resolution of 1200 dpi increasingly available. Print speed is chiefly a function of the frequency with which the nozzles can be made to fire ink drops and the width of the swath printed by the print-head. Typically this is around 12 MHz and half an inch respectively.
Another variant of inkjet, the piezoelectric inkier, uses a piezo crystal at the back of the ink reservoir similar to a loudspeaker conexe2x80x94flexing when an electric current flows through it. So, whenever a dot is required, a current is applied to the piezo element, the element flexes and in so doing forces a drop of ink out of the nozzle.
There are several advantages to the piezo method. The process allows more control over the shape and size of ink droplet release. The tiny fluctuations in the crystal allow for smaller droplet sizes and hence higher nozzle density. Also, unlike with thermal technology, the ink does not have to be heated and cooled between each cycle. This saves time, and the ink itself is tailored more for its absorption properties than its ability to withstand high temperatures. This allows more freedom for developing new chemical properties in inks.
Although there are many benefits such as the possibility to now deposit 1600 dpi, there are also disadvantages to using inkjets to decorate the body. First and foremost are cost and availability of the highly purified and specialized inks or dyes that are able to pass through the inkjet heads or other device passageways. Small particles or impurities in imperfect inks or dyes could cause inkjet head failure. Viscosity, solvent mixture and density must also be precise to avoid failure. Thus it would be advantageous to have a computer-controlled system that is more tolerant to ink or dye composition that is less prone to clogging or print head failure.
Thus it would be beneficial to provide a means for decorating the skin or adnexal structures of an animal or human body using a technology that is digital, relatively rapid, and able to apply a wide range of inexpensive dyes, inks or liquid pigments without the possibility of mechanical failure due to particle size, thermal characteristics, filter clogging, solvent mix composition and ratios or impurity presence. The use of Wirejet(trademark) technology obviates these particular problems. A drawback of the Wirejet(trademark) technology when compared with the newer inkjet technology is that the Wirejet(trademark) is purported to have a limited maximum of 500 dpi resolution as opposed to newer inkjets with 1600 dpi and increasing annually.
Wirejet(trademark) technology has been described in U.S. Pat. Nos 5,944,893 and 5,972,111 to Anderson. The Wirejet(trademark) is in essence a wire xe2x80x9cconveyor beltxe2x80x9d that is externally coated with a liquid pigmented medium via surface tension and adherence upon passing through a given liquid pigment reservoir. The externally coated wire (cable, line, string, cord, etc) then passes in front of a compressed air nozzle whereupon the ink is controllably carried by air (or another gas) to the target medium. In the abstract, Anderson describes the Wirejet(trademark) as a paint injector for digital printing. In Anderson, wheels carry the wire through the paint reservoir whereupon the wire is coated. The wire is further drawn controllably by computer in front of the air stream that pulls the ink or paint from the wire and carries it toward the print medium. By employing a plurality of paint injectors, each with a different color of paint a digital image can be painted by the print head on the print medium. As in inkjet printing, the use of the C,M,Y,K color scheme with white can provide for virtually limitless color combinations.
Wirejet(trademark) technology differs from airbrush technology in which a short, rigid, needle or pin is externally coated with paint or liquid pigment that is then carried onto the target medium by pressurized air from a nozzle.
Another type of print head system differs from the Wirejet(trademark) and is disclosed in U.S. Pat. No. 4,764,780 to Yamamori et al; and may be considered by some to be a variant of an inkjet system. Yamamori is a system designed for inking a recording medium using a plurality of electrically-controlled ink ejection heads connected to a reservoir. As ink is presented by the ejection heads a pressurized air stream is directed by nozzle to carry the ink droplets onto the recording medium. A key difference between the devices of Yamamori and Anderson is that ink is carried internally to the air-stream by Yamamori, while in Anderson the pigmented substance (ink, dye, etc.) is carried from the reservoir to the air-stream externally on wires (or the outer surfaces of lines, cables, strings or cords).
The present invention provides a method for decorating the skin with custom-made, highly detailed, temporary designs. Furthermore, it would be beneficial for the device to apply such skin decorations easily, economically, and quickly, without pain or the risk of injury. The present invention provides a simple and economical process for decorating human skin.
The present invention is a method and apparatus for decorating the human body using Wirejet(trademark) or similar printing technology. An objective of the invention is to print multicolored images on human skin or appendageal products using biocompatible inks or dyes. The decoration is produced by a print head comprising an array of Wirejet(trademark) or other electronically controlled ink ejection nozzles, which can be connected to a scanning mechanism. The print head may be scanned in one, two, or three directions to cover the area of the body to be decorated. Highly contoured anatomic surfaces such as the shoulders, breasts and buttocks may be xe2x80x9cflattenedxe2x80x9d by compression against intersecting restraining wires for proper Wirejet(trademark) application of tattoo inks or dyes. A computer stores the desired design and controls the firing of the apparatus to produce designs on the skin.
In another embodiment, a housing is connected to wheels that are encoded and roll over the skin surface, and a computer synchronizes the firing of the print head nozzles as the housing is moved over the skin. Further enhancement of z-axis capabilities of the current Wirejet(trademark) are herein described that enable the device to better handle the extreme curvatures of the living human or animal body as opposed to the relatively flat or predictably planar and angled print or non-living media that is the current target for Wirejet(trademark) technology.
The described use of the Wirejet(trademark) provides for the opportunity to decorate body surfaces with detailed, temporary personalized designs. If the surface layer of dead skin cells is removed, prior to Wirejet(trademark) tattoo dye or ink application, the decoration will then be applied to the epidermis or upper dermis, and the design will last until those skin layers are sloughed off, which typically takes about a month. These decorations or tattoos, therefore, will last longer than the currently available temporary decal-type tattoos that are transferred to the surface of the skin by rubbing.
Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings.